Objective: To forecast the future trend of betel nut-associated oral cancer and the resulting burden on health based on historical oral cancer patient data in Hunan province, China. Methods: Oral cancer patient data in five hospitals in Changsha (the capital city of Hunan province) were collected for the past 12 years. Three methods were used to analyse the data; Microsoft Excel Forecast Sheet, Excel Trendline, and the Logistic growth model. A combination of these three methods was used to forecast the future trend of betel nut-associated oral cancer and the resulting burden on health.Results: Betel nut-associated oral cancer cases have been increasing rapidly in the past 12 years in Changsha. As of 2016, betel nuts had caused 8,222 cases of oral cancer in Changsha and close to 25,000 cases in Hunan, resulting in about ¥5 billion in accumulated financial loss. The combined trend analysis predicts that by 2030, betel nuts will cause more than 100,000 cases of oral cancer in Changsha and more than 300,000 cases in Hunan, and more than ¥64 billion in accumulated financial loss in medical expenses.Conclusion: The trend analysis of oral cancer patient data predicts that the growing betel nut industry in Hunan province will cause a humanitarian catastrophe with massive loss of human life and national resources. To prevent this catastrophe, China should ban betel nuts and provide early oral cancer screening for betel nut consumers as soon as possible.

Objective: To develop an instrument to measure Oral Health-related Quality of Life (OHQoL) and the changes after dental treatment among older adults in Hong Kong, in order to understand their views on the influences of oral health problems and generate relevant items to design the instrument.Methods: A qualitative study was conducted among adults aged 55 and over. Information on their perceived oral health impacts was collected during semi-structured interviews. A framework approach was used to identify the oral health impacts and to understand the meaning of those impacts on the perception of life satisfaction. Results: A total of 39 participants (average age 72 years) underwent the semi-structured interviews; 20 were seeking dental treatment and 19 had already received dental treatment for 1 to 3 months. In total, 308 statements on oral health impacts were drawn from the participants' descriptions. After four steps of item reduction and refinement, a list of 20 items was generated before being classified into eight domains: Cleansing, Eating, Speaking, Appearance, Social, Psychological, Awareness, and Health and Finance. Conclusion: Older adults in Hong Kong perceive that oral health impacts on different aspects of life. The face validity and content validity of the developed Oral Health Impact on Daily Living (OHIDL) was proved through qualitative study.

Objective: To propose a novel, three-level (severe, moderate, mild) case definition using probing depth (PD), clinical attachment loss (CAL) and bleeding on probing (BOP) for epidemiologic studies on periodontitis.Methods: Case definitions (DEF) 1-30 with PD, CAL and BOP were made. Based on data from epidemiologic research in Chengde (Hebei Province, China) in 1992, prevalence of periodontitis by DEF1-30 was calculated and compared with a reference (definitions by Centers for Disease Control and Prevention/American Academy of Periodontology in 2012). Sensitivity, specificity, Youden Index, Cohen's kappa coefficient (CKC) and the area under the receiver operator characteristic curve (AUC) were calculated for the definitions selected.Results: DEF1 and DEF18 for periodontitis, DEF2, DEF3, DEF19 for moderate and severe periodontitis, and DEF5, DEF13, DEF14, DEF21 and DEF25 for severe periodontitis, which were similar for estimation of periodontitis prevalence compared with the reference, were selected. DEF18 for periodontitis, DEF19 for moderate and severe periodontitis, and DEF5 for severe periodontitis were selected because they showed higher values for the Youden Index, CKC and AUC, and formed a three-level definition.Conclusion: A novel three-level case classification of periodontitis using three parameters of PD, CAL and BOP was proposed. The estimated periodontitis prevalence according to the novel proposed definition is close to the prevalence according to the CDC/AAP definition.

Objective: To analyse factors associated with the susceptibility of early childhood caries (ECC), populations with a high risk of ECC were screened and guidance for ECC prevention was proposed. Methods: A total of 392 children aged 24 to 71 months were selected for oral examination in Qingdao. Parents or guardians of the participants completed the questionnaires and decayed missing filled surface (dmfs) were recorded. Differences in caries condition and oral health behaviour in different families were compared. Risk factors related to ECC were screened. The subjects were finally grouped based on the obtained dmfs into three groups: caries-free, ECC and S-ECC (severe ECC). Association of risk factors with the caries status was analysed using the Kruskal-Wallis test, the chi-square test and logistic regression analysis. Results: There were significant differences among the caries-free, ECC and S-ECC groups in three parameters: eating too many sweets each day, brushing before and after sleeping, and whether parents helped to brush (P < 0.01). Combined factors such as the parents' level of education, oral health knowledge, attitudes, the family's annual income, the age of children when they start to brush and not brushing regularly were also significantly related to ECC (P < 0.05). No significant differences were observed among the three groups for these factors, including birth condition and nursing state, physical condition of the mother during pregnancy, feeding situation, if a pacifier was used during sleep, duration of brushing, frequency of mouth rinsing after meals each day and brushing with fluoride toothpaste (P > 0.05). Conclusion: Eating a lot of sweets, an incorrect brushing method, starting brushing at a later stage and not brushing regularly are susceptible factors for ECC. Emphasising oral health knowledge to parents and guardians, conducting proper brushing methods, limiting the frequency of sweets being eaten and avoiding an inappropriate habit of eating sweets are very important factors in the prevention of ECC.

Objective: To explore the effects of the combination of insulin-like growth factor 1 (IGF-1) and platelet-derived growth factor (PDGF) on bone formation around dental implants.Methods: A total of 24 adult rabbits were included in this experiment. Titanium machine-polished dental implants were placed in the iliac bones to simulate dental implants in the alveolar bone. The rabbits were randomly divided into four groups; a saline treated control group (NS), an IGF-1 treated group, a PDGF-BB treated group, and a combination of IGF-1 and PDGF-BB treated group. The rabbits were sacrificed after 3, 7, and 10 days, and implants and soft tissues around implants were histologically evaluated.Results: All of the rabbits began to recover their appetite, move freely and the operation area started detumescence until after the fourth day. H&E staining showed that the granulation tissue formation, multinucleated giant cells, a small amount of calcium salt deposition and bone tissue were observed in the IGF-1 group and the PDGF-BB group. In the IGF-1 + PDGF-BB group, the granulation tissue had turned into fibrous connective tissue, and calcium salt deposit had formed bone tissue. Masson's trichrome staining showed that the IGF-1 group and the PDGF-BB group had more collagen fibre compared with the NS group. In the IGF-1 + PDGF-BB group, collagen fibre hyperplasia and repairing fibres appeared earlier than in other groups.Conclusion: When applying IGF-1 or PDGF-BB alone, either has the effect of accelerating the wound healing in the short term; while in combination, earlier collagen fibre hyperplasia appeared.

Malignant melanoma of the mandibular gingiva is extremely rare. It is a malignant tumour of melanocytes or their precursor cells, and often misinterpreted as a benign pigmented process. A few reports have described computed tomography (CT) and magnetic resonance imaging (MRI) findings of malignant melanoma in the oral cavity. We report a rare case of malignant melanoma of the mandible and the related CT and MRI findings. Soft tissue algorithm contrast-enhanced CT showed an expansile mass and irregular destruction of alveolar bone in the right side of the mandibular molar area. MR images showed an enhancing mass and the tumour had a low to intermediate signal intensity and a high-signal intensity. Soft tissue algorithm contrast-enhanced CT and MR images showed lymphadenopathy involving the submandibular lymph nodes. Histopathological examination confirmed the diagnosis of malignant melanoma.